<?php
/**
 * SimplePie
 *
 * A PHP-Based RSS and Atom Feed Framework.
 * Takes the hard work out of managing a complete RSS/Atom solution.
 *
 * Copyright (c) 2004-2012, Ryan Parman, Geoffrey Sneddon, Ryan McCue, and contributors
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 *    * Redistributions of source code must retain the above copyright notice, this list of
 *      conditions and the following disclaimer.
 *
 *    * Redistributions in binary form must reproduce the above copyright notice, this list
 *      of conditions and the following disclaimer in the documentation and/or other materials
 *      provided with the distribution.
 *
 *    * Neither the name of the SimplePie Team nor the names of its contributors may be used
 *      to endorse or promote products derived from this software without specific prior
 *      written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS
 * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * @package SimplePie
 * @version 1.3.1
 * @copyright 2004-2012 Ryan Parman, Geoffrey Sneddon, Ryan McCue
 * @author Ryan Parman
 * @author Geoffrey Sneddon
 * @author Ryan McCue
 * @link http://simplepie.org/ SimplePie
 * @license http://www.opensource.org/licenses/bsd-license.php BSD License
 */

/**
 * Used for feed auto-discovery
 *
 *
 * This class can be overloaded with {@see SimplePie::set_locator_class()}
 *
 * @package SimplePie
 */
class SimplePie_Locator
{
    var $useragent;
    var $timeout;
    var $file;
    var $local = array();
    var $elsewhere = array();
    var $cached_entities = array();
    var $http_base;
    var $base;
    var $base_location = 0;
    var $checked_feeds = 0;
    var $max_checked_feeds = 10;
    protected $registry;

    public function __construct(SimplePie_File $file, $timeout = 10, $useragent = null, $max_checked_feeds = 10)
    {
        $this->file = $file;
        $this->useragent = $useragent;
        $this->timeout = $timeout;
        $this->max_checked_feeds = $max_checked_feeds;

        if (class_exists('DOMDocument')) {
            $this->dom = new DOMDocument();

            set_error_handler(array('SimplePie_Misc', 'silence_errors'));
            $this->dom->loadHTML($this->file->body);
            restore_error_handler();
        } else {
            $this->dom = null;
        }
    }

    public function set_registry(SimplePie_Registry $registry)
    {
        $this->registry = $registry;
    }

    public function find($type = SIMPLEPIE_LOCATOR_ALL, &$working)
    {
        if ($this->is_feed($this->file)) {
            return $this->file;
        }

        if ($this->file->method & SIMPLEPIE_FILE_SOURCE_REMOTE) {
            $sniffer = $this->registry->create('Content_Type_Sniffer', array($this->file));
            if ($sniffer->get_type() !== 'text/html') {
                return null;
            }
        }

        if ($type & ~SIMPLEPIE_LOCATOR_NONE) {
            $this->get_base();
        }

        if ($type & SIMPLEPIE_LOCATOR_AUTODISCOVERY && $working = $this->autodiscovery()) {
            return $working[0];
        }

        if ($type & (SIMPLEPIE_LOCATOR_LOCAL_EXTENSION | SIMPLEPIE_LOCATOR_LOCAL_BODY | SIMPLEPIE_LOCATOR_REMOTE_EXTENSION | SIMPLEPIE_LOCATOR_REMOTE_BODY) && $this->get_links()) {
            if ($type & SIMPLEPIE_LOCATOR_LOCAL_EXTENSION && $working = $this->extension($this->local)) {
                return $working;
            }

            if ($type & SIMPLEPIE_LOCATOR_LOCAL_BODY && $working = $this->body($this->local)) {
                return $working;
            }

            if ($type & SIMPLEPIE_LOCATOR_REMOTE_EXTENSION && $working = $this->extension($this->elsewhere)) {
                return $working;
            }

            if ($type & SIMPLEPIE_LOCATOR_REMOTE_BODY && $working = $this->body($this->elsewhere)) {
                return $working;
            }
        }
        return null;
    }

    public function is_feed($file)
    {
        if ($file->method & SIMPLEPIE_FILE_SOURCE_REMOTE) {
            $sniffer = $this->registry->create('Content_Type_Sniffer', array($file));
            $sniffed = $sniffer->get_type();
            if (in_array($sniffed, array('application/rss+xml', 'application/rdf+xml', 'text/rdf', 'application/atom+xml', 'text/xml', 'application/xml'))) {
                return true;
            } else {
                return false;
            }
        } elseif ($file->method & SIMPLEPIE_FILE_SOURCE_LOCAL) {
            return true;
        } else {
            return false;
        }
    }

    public function get_base()
    {
        if ($this->dom === null) {
            throw new SimplePie_Exception('DOMDocument not found, unable to use locator');
        }
        $this->http_base = $this->file->url;
        $this->base = $this->http_base;
        $elements = $this->dom->getElementsByTagName('base');
        foreach ($elements as $element) {
            if ($element->hasAttribute('href')) {
                $base = $this->registry->call('Misc', 'absolutize_url', array(trim($element->getAttribute('href')), $this->http_base));
                if ($base === false) {
                    continue;
                }
                $this->base = $base;
                $this->base_location = method_exists($element, 'getLineNo') ? $element->getLineNo() : 0;
                break;
            }
        }
    }

    public function autodiscovery()
    {
        $done = array();
        $feeds = array();
        $feeds = array_merge($feeds, $this->search_elements_by_tag('link', $done, $feeds));
        $feeds = array_merge($feeds, $this->search_elements_by_tag('a', $done, $feeds));
        $feeds = array_merge($feeds, $this->search_elements_by_tag('area', $done, $feeds));

        if (!empty($feeds)) {
            return array_values($feeds);
        } else {
            return null;
        }
    }

    protected function search_elements_by_tag($name, &$done, $feeds)
    {
        if ($this->dom === null) {
            throw new SimplePie_Exception('DOMDocument not found, unable to use locator');
        }

        $links = $this->dom->getElementsByTagName($name);
        foreach ($links as $link) {
            if ($this->checked_feeds === $this->max_checked_feeds) {
                break;
            }
            if ($link->hasAttribute('href') && $link->hasAttribute('rel')) {
                $rel = array_unique($this->registry->call('Misc', 'space_seperated_tokens', array(strtolower($link->getAttribute('rel')))));
                $line = method_exists($link, 'getLineNo') ? $link->getLineNo() : 1;

                if ($this->base_location < $line) {
                    $href = $this->registry->call('Misc', 'absolutize_url', array(trim($link->getAttribute('href')), $this->base));
                } else {
                    $href = $this->registry->call('Misc', 'absolutize_url', array(trim($link->getAttribute('href')), $this->http_base));
                }
                if ($href === false) {
                    continue;
                }

                if (!in_array($href, $done) && in_array('feed', $rel) || (in_array('alternate', $rel) && !in_array('stylesheet', $rel) && $link->hasAttribute('type') && in_array(strtolower($this->registry->call('Misc', 'parse_mime', array($link->getAttribute('type')))), array('application/rss+xml', 'application/atom+xml'))) && !isset($feeds[$href])) {
                    $this->checked_feeds++;
                    $headers = array(
                        'Accept' => 'application/atom+xml, application/rss+xml, application/rdf+xml;q=0.9, application/xml;q=0.8, text/xml;q=0.8, text/html;q=0.7, unknown/unknown;q=0.1, application/unknown;q=0.1, */*;q=0.1',
                    );
                    $feed = $this->registry->create('File', array($href, $this->timeout, 5, $headers, $this->useragent));
                    if ($feed->success && ($feed->method & SIMPLEPIE_FILE_SOURCE_REMOTE === 0 || ($feed->status_code === 200 || $feed->status_code > 206 && $feed->status_code < 300)) && $this->is_feed($feed)) {
                        $feeds[$href] = $feed;
                    }
                }
                $done[] = $href;
            }
        }

        return $feeds;
    }

    public function get_links()
    {
        if ($this->dom === null) {
            throw new SimplePie_Exception('DOMDocument not found, unable to use locator');
        }

        $links = $this->dom->getElementsByTagName('a');
        foreach ($links as $link) {
            if ($link->hasAttribute('href')) {
                $href = trim($link->getAttribute('href'));
                $parsed = $this->registry->call('Misc', 'parse_url', array($href));
                if ($parsed['scheme'] === '' || preg_match('/^(http(s)|feed)?$/i', $parsed['scheme'])) {
                    if (method_exists($link, 'getLineNo') && $this->base_location < $link->getLineNo()) {
                        $href = $this->registry->call('Misc', 'absolutize_url', array(trim($link->getAttribute('href')), $this->base));
                    } else {
                        $href = $this->registry->call('Misc', 'absolutize_url', array(trim($link->getAttribute('href')), $this->http_base));
                    }
                    if ($href === false) {
                        continue;
                    }

                    $current = $this->registry->call('Misc', 'parse_url', array($this->file->url));

                    if ($parsed['authority'] === '' || $parsed['authority'] === $current['authority']) {
                        $this->local[] = $href;
                    } else {
                        $this->elsewhere[] = $href;
                    }
                }
            }
        }
        $this->local = array_unique($this->local);
        $this->elsewhere = array_unique($this->elsewhere);
        if (!empty($this->local) || !empty($this->elsewhere)) {
            return true;
        }
        return null;
    }

    public function extension(&$array)
    {
        foreach ($array as $key => $value) {
            if ($this->checked_feeds === $this->max_checked_feeds) {
                break;
            }
            if (in_array(strtolower(strrchr($value, '.')), array('.rss', '.rdf', '.atom', '.xml'))) {
                $this->checked_feeds++;

                $headers = array(
                    'Accept' => 'application/atom+xml, application/rss+xml, application/rdf+xml;q=0.9, application/xml;q=0.8, text/xml;q=0.8, text/html;q=0.7, unknown/unknown;q=0.1, application/unknown;q=0.1, */*;q=0.1',
                );
                $feed = $this->registry->create('File', array($value, $this->timeout, 5, $headers, $this->useragent));
                if ($feed->success && ($feed->method & SIMPLEPIE_FILE_SOURCE_REMOTE === 0 || ($feed->status_code === 200 || $feed->status_code > 206 && $feed->status_code < 300)) && $this->is_feed($feed)) {
                    return $feed;
                } else {
                    unset($array[$key]);
                }
            }
        }
        return null;
    }

    public function body(&$array)
    {
        foreach ($array as $key => $value) {
            if ($this->checked_feeds === $this->max_checked_feeds) {
                break;
            }
            if (preg_match('/(rss|rdf|atom|xml)/i', $value)) {
                $this->checked_feeds++;
                $headers = array(
                    'Accept' => 'application/atom+xml, application/rss+xml, application/rdf+xml;q=0.9, application/xml;q=0.8, text/xml;q=0.8, text/html;q=0.7, unknown/unknown;q=0.1, application/unknown;q=0.1, */*;q=0.1',
                );
                $feed = $this->registry->create('File', array($value, $this->timeout, 5, null, $this->useragent));
                if ($feed->success && ($feed->method & SIMPLEPIE_FILE_SOURCE_REMOTE === 0 || ($feed->status_code === 200 || $feed->status_code > 206 && $feed->status_code < 300)) && $this->is_feed($feed)) {
                    return $feed;
                } else {
                    unset($array[$key]);
                }
            }
        }
        return null;
    }
}

